Lubricant



?ateni:eri Aug. 8, 1939 taunt i i E e i e LUBRICANT diana No Drawing. Application December 5, 1936, Serial No. 1l4,435

4 Claims.

This invention relates to lubricants and, in particular, to addition agents imparting to lubricants improved properties.

Our invention has particular utility in preventing and/or inhibiting the corrosion of hard metal alloy bearings such as copper-lead, cadmiumnickel, and cadmium-silver bearings which, to a large extent, have replaced soft metal bearings such as Babbitt metal in the trend toward internal combustion engines having high compression ratios and increased acceleration and increased speed characteristics. The use of the hard metal bearings has created lubricatingand corrosion problems, particularly in connection with highly refined oils, some of which may be very corrosive to the hard metal bearings.

By highly refined lubricating oils we mean viscous oils which have a minimum viscosity in the range of S. A. E. 10 oils, and which'have been subjected to such refining processes such as, for example, solvent extraction, that the parafiinicity of the oil is markedly increased. It has been found that highly refined lubricating oils cause corrosion to alloy bearings of the cadmium-silver type to the extent of 5 mg/cm. and even greater when such bearings are submerged for hours or less in an air agitated oil which has been preoxidized at about 340 F. for 25 to 50 hours. The motor oils may be highly refined lubricating oils as such or mixtures of highly refined lubricating oils with less highly refined lubricating oils, or stated in another way, mixtures of corrosive oils and non-corrosive oils, examples of the latter being lubricating oil fractions from Winkler crude or crudes of the Winkler type.

We have found that corrosion of hard metal bearing alloys of the cadmium-silver type due to corrosive highly refined lubricating oil can be inhibiting and other desirable properties can be imparted to lubricating oils by adding to said oils certain organic compounds, particularly the alkyl or aryl derivatives of an acid selected from the group consisting of cyanic acid, isocyanic acid, hydrocyanic acid and isohydrocyanic acid. The

' terms alkyl or aryl derivatives as used herein include the alkyl and aryl radicals and said radicals substituted with alkoxy, amines, mercapto, halogen or other substituent group or groups and/ or mixtures thereof.

Below are examples of alkyl or aryl derivatives of cyanic acid and isocyanic acid which have the general formula ROCN or RNCO in which R is an alkyl or aryl radical:

octyl isocyanate phenyl isocyanate isobutyl isocyanate propyl isocyanate Examples of the alkyl. or aryl derivatives of hydrocyanic acid and isohydrocyanic acid having the general formula RCN or RNC in which R is an alkyl or aryl radical are listed below:

octyl cyanide cetyl nitrile trimethyl acetonitrile phenyl acetonitrile lauryl nitrile alpha naphthyl nitrile stearonitrile benzonitrile octyl isocyanide In addition'to the alkyl or aryl derivatives of the cyanic acids and the hydrocyanic acids we may use the fatty acid thiocyanates having the general formula in which R is an alkyl radical, such as .lauroyl thiocyanate, stearoyl thiocyanate, etc. We may also use the thiocyan ketones having the general formula in which R and R are alkyl radicals such as alpha thiocyanoamyl-butyl ketone, alpha thiocyano stearone, etc.

While we may use any alkyl or aryl derivative of the hereinbefore disclosed acids we prefer to use those derivatives having a boiling point of about 400 F. or higher in order to avoid volatization of the addition agent at the temperature attained in internal combustion engines during operation.

As has been heretofore mentioned many of the recent models of automobiles now in use are equipped with bearings of the hard metal alloy type such as cadmium-silver alloy, cadmiumnickel alloy, copper-lead alloy, etc. for the purpose of permitting increased speed characteristics and increased acceleration. Also in recent years mineral lubricating oils adapted for use in internal combustion engines have been more drastically refined by acid treatment and/or solventextraction for the purpose of improving certain properties thereof suchas the viscosity index, sludge stability and the like. While oils so refined give satisfactory performance in many respects they have been found to cause more or less trouble in internal combustion engines equipped with bearings of the cadmium-silver type due to the corrosion of such alloys. We have found that the addition of very small amounts, such as 0.01% to 0.75% of the compounds hereinbefore disclosed, to corrosive highly refined motor oils will inhibit the corrosion of such alloys.

These compounds may also be used to impart other desirable properties to lubricating oils such as non-stickingring properties and the like.

Under certain conditions some of the compounds falling within the class herein disclosed may not be completely soluble in the lubricant,

as defined by the appended claims.

We claim: f

1. The method of lubricating internal combustion engines provided with hard metal alloy bearings having the corrosive susceptibility of alloys of the class consisting of cadmium-silver,

cadmium-nickel and copper-lead alloys, which comprises-applying to said bearings a lubricant comprising a highly refined lubricating oil normally corrosive to said bearings and ahydrocarbon isocyanate having the general formula RNCO in which R." is a hydrocarbon group, said hydrocarbon isocyanate being used in a small but suflicient proportion to substantially inhibit the corrosion of said bearings. -v

2. The method of lubricating internal combus tion engines provided with hard metal alloy bearings having thecorrosive susceptibility of I alloys of the class consisting of cadmium-silver,

cadmium-nickel and copper-lead alloys,- which comprises applying to said bearings a lubricant comprising .a highly refined lubricating oil normally corrosive to said bearings and an alkyl cyanide having the general formula RUN in which R is an alkyl radical, said alkyl cyanide being used in a small but suflicient proportion to substantially inhibit the corrosion of said bearings.

3. The method of lubricating internal combustion engines provided with hard metal alloy bearings having the corrosive susceptibility of alloys of the class consisting of cadmium-silver, cadmium-nickel and copper-lead alloys, which comprises applying to'said bearings a lubricant comprising a highly refined lubricating oil normally corrosive to said bearings and an aryl cyanide having the general formula RCN in which R" is an aryl radical, said aryl cyanide being used in a small butsuflicient proportion to substantially inhibit the corrosion of said bearings.

4; The methodof lubricating internal com-' bustionengines provided with hard metal alloy bearings having the corrosive susceptibility of alloys of the class consisting of, cadmiumsilver, cadmium-nickel and copper-lead alloys which comprises applying to said bearings a lubricant comprising a highly refined lubricating oil nor- -mally corrosive to said bearings and, an organic compound selected from the group consisting of hydrocarbon cyanates having the general formula RDCN, hydrocarbon isocyanates having the general formula RNCO', hydrocarbon cyanides having the general formula RCN, and hydrocarbon isocyanides having the general formula RNC,vin which 'R in each instance is a radical selected from the group consisting of. alkyl radicals and aryl radicals; said organic compound being used in a, small but sufilcient proportion to substantially inhibit the corrosion or said bearings. l

' CLARENCE M. LOANE.

BERNARD H. SHOEMAKER. 

